The present invention relates to conveyor systems and methods, and more particularly to systems and methods for transferring product to, from, or between conveying systems while performing product processing operations upon the product being transferred.
Continued advances in material handling and processing systems have generated increased demand for systems that are faster and more versatile than their earlier counterparts. This fact is well demonstrated in systems that process and convey paper product, such as stacks of napkins, kitchen and bathroom toweling, and the like. Such product is often stacked or wound into elongated stacks or rolls (referred to herein as xe2x80x9clogsxe2x80x9d) for downstream processing such as log cutting, sealing, and the like. It should be noted that reference in the present application and appended claims to xe2x80x9clogsxe2x80x9d of material or xe2x80x9cproductxe2x80x9d include rolled, stacked, or bundled product made of any material, such as paper, plastic, rubber, metal, composites, fabric, and the like. However, for purposes of discussion and example only, the terms xe2x80x9clogxe2x80x9d and xe2x80x9cproductxe2x80x9d in the remainder of this specification refers to an elongated stack of folded napkins.
A problem that continues to exist in log processing and conveying systems (as well as in many other material processing and conveying systems) is the transfer of logs during a log processing operation from one conveying surface to another. For example, long logs of napkins or long logs of wound toilet paper typically need to be cut into shorter user-sized stacks or rolls prior to being packaged. Log cutting operations usually require a minimal gap in the log conveying system through which a blade is passed to cut the passing logs. In log saw and other log processing operations, this gap can be larger or smaller depending upon a number of factors such as space constraints, log speed, machine speed (e.g., saw speed), and the like. Even the type of machine used can affect the gap size required between conveying surfaces. A log saw may require much greater space between conveying surfaces to perform its cutting operation than a log bander or other device. Regardless of the type of machine involved, however, logs passing a gap between conveying surfaces often must be supported or constrained as they pass the gap. Specifically, some logs can sag, fan, or expand prior to crossing the gap to a downstream conveying surface or need support while an operation is performed upon the portion of the log spanning the gap. In conventional log handling and processing systems, a popular remedy for this problem is to attach log support members to one or both conveying surfaces beside the gap. The log support members therefore move with their attached conveying surface(s) and move into and out of the gap as the conveying surface(s) move product through the gap.
Conventional designs such as the one just described for guiding, supporting, and/or feeding logs between conveying surfaces have a very limited ability to accept changes to system operation. Conventional systems generally have no ability to quickly vary the gap between the upstream and downstream conveying surfacesxe2x80x94either during product processing or between processing runs. It is often desirable to vary this gap for a number of different reasons, including without limitation to adjust for changes in product speed, machine speed, (e.g., the orbiting speed of a log saw), and log material, dimensions, or shape. For many conventional systems, a user can only change the gap by stopping the system, detaching and removing the log support members from the conveying surfaces, and replacing and attaching shorter or longer log support members on the conveying surfaces. Longer support members are able to span larger gaps, while shorter support members are installed for narrower gaps. Especially where system or log changes are frequently made (thereby calling for changes in gap size), significant production time is lost in changing the support members to adjust for different gap sizes. In addition to being difficult and time consuming to adjust, such systems are expensive to manufacture and maintain, require a user to keep an inventory of different log support types, and generally do not permit xe2x80x9con-the-flyxe2x80x9d user adjustability in response to gap changes.
In light of the problems and limitations of the prior art described above, a need exists for a conveyor product transfer apparatus and method for transferring product to, from, or between conveying surfaces separated by a gap, which supports or at least partially restrains product as it passes the gap and as a product processing operation (e.g., cutting) is performed upon the product, which is relatively simple and inexpensive to manufacture and maintain, which is well-suited for product transfer where different gap widths are required, and which can be quickly adjusted without system shutdown or disassembly. Each preferred embodiment of the present invention achieves one or more of these results.
The conveyor product transfer apparatus of the present invention includes at least one product transfer member mounted for movement between product conveying surfaces or between a discharge or receiving station and a conveying surface separated by a distance sufficient to provide equipment clearance for an operation performed upon the product transferred by the transfer member. Preferably, the product transfer member is mounted for movement having a translational component and most preferably for movement that is substantially translational. The movement of the product transfer member is preferably reciprocating. Also preferably, the operation performed upon the product transferred is a log saw cutting operation and the equipment is a log saw, but the present invention can also be used in conjunction with numerous other applications requiring the above-mentioned clearance.
Different applications of the present invention can employ any number of transfer members. In one preferred embodiment, each transfer member is mounted for reciprocating, substantially translational movement between ends of conveying surfaces that are separated a distance apart, and has a sliding member in sliding engagement with a track to facilitate such movement. Each transfer member is coupled to an actuation assembly for movement thereof. The actuation assembly is most preferably a camshaft assembly transferring rotational driving power received from a motor or other conventional driving device to at least partially translational motion for moving the connected transfer member through its product stations, although any mechanism for providing such translational movement can be used. The product stations include a product receiving station located adjacent to a conveying surface for receiving product from the conveying surface, a processing station (which in a preferred embodiment of the present invention is a product cutting station), and a product discharge station located a distance from the product receiving station. Depending upon where the product is cut in the gap between the conveying surfaces, the product cutting station can be at least partly located at the product receiving or product discharge stations. The transfer member(s) move with product passing the gap to support the product in the gap or to at least partially contain the product in the gap. Because the transfer members preferably reciprocate, the transfer members can pass through their stations multiple times for longer products being processed.
The transfer member(s) preferably provide support for the product through the gap until the product is discharged to a downstream conveying surface. Accordingly, the speed of the product or machine and the size of the gap needed to complete a particular operation (such as product cutting) is irrelevant because the support moves with the product, unlike conventional systems which require changing support members when product sizes or machine speeds change.
In another preferred embodiment of the present invention, two transfer members face one another and move together with product passed therebetween. In other embodiments, one transfer member reciprocates between conveying surfaces separated a distance apart and acts primarily to support the product from underneath as it passes from the upstream conveying surface to the downstream conveying surface.
To support the conveyed product during product processing operations (e.g., product cutting) in the gap, the present invention also preferably includes a kick member mounted for movement into and out of the gap between the conveying surfaces. In product cutting operations, the kick member preferably backs the product being cut adjacent to the saw blade and preferably is timed to move away from the gap after the product has been cut. Most preferably, this motion is a reciprocating motion generated by a camshaft and cam assembly coupled to the kick member.
At least one of the upstream conveying surfaces preferably has an end roller and an end plate adjacent to the gap and to the product receiving station of the transfer member to help provide smooth product transfer from the upstream conveying surface to the transfer member. An end roller and/or an end plate can also be located on facing upstream conveying surfaces or even on downstream conveying surfaces if desired.
In operation of the present invention, product is received by the transfer member(s) driven to move with the conveyed product through at least part of the gap to a downstream location where the product is discharged from the transfer member(s). Preferably, product is transferred between upstream conveying surfaces and downstream conveying surfaces by transfer members which move through substantially the entire gap between the conveying surfaces. Also preferably, two transfer members are driven by respective actuation assemblies (which preferably are camshaft assemblies). Where the kick member is employed, the log saw cuts the product while the kick member is in a product supporting position backing the product in the gap. Most preferably, the transfer member camshaft assemblies and the connected transfer members are driven by a series of belts and pulleys that are coupled to and driven by the same motor that drives the log saw. Therefore, the transfer members preferably move in synchronicity with the log saw so that cutting operations occur at a desired transfer member location in the gap. The kick member is also preferably driven by a series of belts and pulleys that are coupled to and driven by the same motor that drives the log saw. Therefore, the kick member preferably also moves in synchronicity with the log saw so that the kick member is in its product supporting position while the saw is cutting the product.